Predicting reservoir characteristics in tight-gas sandstone reservoirs, such as those of the Upper Cretaceous units of the Piceance basin, is difficult due to the interactions of multiple processes acting on sediments during basin development. To better understand the dynamics of these systems, a forward numerical model, which accounts for compaction, fracturing, hydrocarbon generation, and multiphase flow (BasinRTM) is used in a one-dimensional simulation of the U.S. Department of Energy's Multiwell Experiment (MWX) site in the Piceance basin. Of particular interest is the effect of gas generation on the dynamics of the system. Comparisons of predicted present-day and observed reservoir characteristics show that the simulation generally captures the observed patterns. Analysis of the simulated history of the MWX site shows that theologic properties constrain the distribution of fractures, whereas the fracture dynamics are controlled by the dynamics of the stress and fluid pressure histories. Results suggest that gas generation is not necessary to induce fracturing; however, by contributing to overpressure it has two important implications: (1) during maximum burial, gas saturation in one unit affects fracturing in other units, thereby contributing to the creation of flow conduits through which gas may migrate and (2) gas saturation helps sustain overpressure during uplift and erosion, allowing fractures to remain open.